Interaction between wind turbines and the radar systems operated by the meteorological services

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1 Interaction between wind turbines and the radar systems operated by the meteorological services Challenges facing the DWD Carmen Diesner, Measurement Technology Division (TI 22), Deutscher Wetterdienst, Frankfurter Straße 135, Offenbach, Germany

2 Table of contents DWD's legal mandate Radar network of the DWD Conflict between weather radar systems and wind turbines Consequences for the DWD Challenges facing the DWD Activities of the DWD Results from the study carried out at Graz University of Technology International considerations Outlook

3 Legal mandate The Deutscher Wetterdienst (DWD) is the national meteorological service of Germany and as such a public institution with partial legal capacity under the department of the Federal Ministry of Transport and Digital Infrastructure (BMVI). The DWD's legal basis is found in section 74, para 1, No. 21 of the German Basic Law. The DWD's tasks are set out in the 'Law on the Deutscher Wetterdienst" of 10 Sept (Federal Law Gazette I, p. 287). The tasks include, among other things: the provision of meteorological services the meteorological safeguarding of aviation and shipping, the issuance of official warnings of weather occurrences that could become a danger for public safety and order, especially concerning the impending danger of floods, various duties in the context of civil defence and civilian-military collaboration the monitoring of the atmosphere and the climate operation of the necessary measurement and observation systems

4 Involvement of DWD in authorisation processes As a federal authority defending public interests, the DWD has special rights, including the right to be informed by authorising authorities, for example in case of matters relating to Section 35, para. 1 and 3 (No. 8), of the Federal Building Code (BauGB) Section 10, para. 5, of the Federal Immission Control Act (BImSchG) Authorising authorities have to consider all statements relating to a project, ponder the alternatives and decide about their relevance. DWD explains the problem and formulates the requirements but the legal force of DWD requirements are put into question (by wind turbine operators, lawyers, etc.). Decision-making power lies with local and rural district authorities. All requests are subjected to a technical assessment at the DWD. official involvement preliminary enquiries, e.g. whether a project would infringe the DWD's interests Germany being a federal country, the competence for planning wind energy systems lies with the individual Länder (federal states).

5 Radar network of the DWD 17 operational radar sites + 1 radar system for quality assurance Modernisation and upgrading to dual-polarisation radars until 2015 at an estimated cost of around 30 million euros The one and only weather radar network in Germany Weather radars are the only available technology providing full three-dimensional coverage of precipitation and wind data. Data are used by internal and external customers for forecast purposes aeronautical meteorological consultation disaster management hydrology numerical weather prediction

6 Conflict: weather radar vs. wind turbines Weather radar and wind turbines are competing for similar sites: exposed location (top of hill), outside built-up areas horizon without obstacles infrastructure available highly limited choice of weather radar sites due to the necessity of homogeneous distribution over Germany high societal importance

7 Example of disturbance: Rostock Rostock weather radar Wind park of Admannshagen Warning thresholds: 46 dbz: severe weather 55 dbz: hail warning

8 Consequences for the DWD Weather forecasting and warnings Automatic procedures produce erroneous warnings. Too many or too rare warnings Warnings lose their credibility. Attribution at the small scale and extension of lead times not possible More difficult for the meteorologists to analyse high-impact weather situations Wrong information, e.g. for aeronautical meteorological consultancy services Quantitative precipitation monitoring Inaccuracy in hydrological applications No precise climate monitoring possible Numerical weather prediction Erroneous initialisation of the DWD's weather forecasting models Verification of model forecasts may possibly be based on erroneous measurements. The fulfilment of the DWD's statutory tasks is put at risk!

9 Challenges facing the DWD Respect for the DWD's interests Development of a procedure for eliminating disturbances produced by wind turbines, while continuing to receive the meteorological information maintaining the quality of radar data continuing to further develop and refine the methods in order to be able to meet the increasing demands for temporally and spatially better resolved forecasts and warnings Development of possibilities of coexistence of wind turbines and weather radars at the various levels (processors, product generation, planning, etc.) Legal disputes discussion of strategic solutions Ensure the DWD's capacity to work successfully and fufil its statutory tasks

10 Activities of the DWD Case-by-case evaluation of each application based on standardised criteria Information leaflet about height and distance requirements Information events for local and regional government and planning authorities Inclusion of the DWD's requirements into the development plans both at regional and Land-level Scientific exchange at the national and international level, Participation in the WERAN project of the National Metrology Institute of Germany (PTB; WERAN Interaction of Wind Turbines and Radar/Navigation Systems) Ordering a study into the impacts of wind turbines on the DWD's weather radar systems Co-operation on the development of solution approaches

11 Study by Graz University of Technology Ongoing study by the Institute of Microwave and Photonic Engineering of Graz University of Technology Close look at three radar sites: Emden, Ummendorf and Neuheilenbach Period examined by the study: 2 years Examination of different data times during the day and different seasons and various weather situations Aim of the study to compile a register of wind turbines (finished) to provide qualitative evidence of wind turbine impacts, using 5 products as a basis (e.g. KONRAD - Konvektive Entwicklung in Radarprodukten) (finished) to quantitatively evaluate the impact of wind turbines on reflectivity and radial wind measurements (finalisation in progress) to assess the sensitivity of radar products to interfering signals from wind turbines (finalisation in progress) Prolongation of the study in order to analyse dual-polarisation data

12 International considerations on the issue of weather radar vs. wind turbines Most of the European countries, as well as the USA and Canada, are encountering problems with the siting of wind turbines close to weather radar sites. The DWD participates in the efforts of European co-operations (EUMETNET, OPERA) and others to examine the issue and work out solutions. At European level, the following restrictions were agreed for C-band radars: within a radius of 5 km: no WT within a radius of 20 km: case-by-case verification of the wind turbine As a compromise, the DWD requests only 15 km. The World Meteorological Organization (WMO) has adopted this agreement as an internationally binding rule and has made it a recommendation for all national meteorological services. Internationally, there is no method known which could avoid, reduce or eliminate these operational disturbances.

13 Outlook Prolongation of the study by Graz University of Technology towards dualpolarisation data Joint workshop of DWD and the FA Wind, Onshore Wind Energy Agency about the coexistence of wind energy and weather radar systems Agreement on the future course of action once the results from the various measures are available: study by Graz University of Technology WERAN scientific workshop OPERA etc.

14 Thank you very much for your attention.